In the conventional rotary grinding mechanism for a condiment grinder, coaxial inner and outer grinding elements are provided. The outer element is fixedly received in the main body of the grinder, with the inner element received to rotate within the outer element. The opposing grinding faces of the grinding elements are tapered or generally conical grinding faces such that relative axial adjustment between the elements can be used to adjust the fineness of the ground condiment. Although some grinding mechanisms are bi-directional, for efficient grinding uni-directional grinding mechanisms are employed that have grinding faces with teeth, grooves or ribs arranged directionally relative to the axis of rotation (e.g. circumferentially tapered in a right-handed helical pattern) for satisfactory performance in one direction of rotation only.
Dual condiment grinders meet a need for a grinder which can be used to dispense both freshly ground salt and pepper. U.S. Pat. No. 4,709,865 describes a dual condiment grinder of the above-mentioned type having separate compartments for each condiment, each having a respective grinding mechanism at the base of the container, both grinding mechanisms being operable by a single handle. A shaft for rotatably driving each of the grinding mechanisms, extends upwardly through its associated compartment and has a spur gear fixedly attached to the upper end thereof. A pivotally supported gear drive mechanism is provided at the top of the compartments which engages the gear of one of the grinding mechanisms when rotated in one direction and the gear of the other of the grinding mechanisms when rotated in an opposite direction. A drawback with this grinder is that, for best performance, two different directional grinding mechanisms are required. Alternatively, production costs can be reduced with the use of two like bi-directional grinding mechanisms, however this compromises the performance of the grinder. It is an object of the present invention to overcome or substantially ameliorate the above disadvantages or more generally to provide an improved grinder.